Moon may have viscous layer between core and mantle

Ars Technica : The Moon’s gravitational pull on Earth, as evidenced by the oceans’ tides, has long been recognized; however, Earth also exerts a reciprocal pull on the Moon. That pull creates seismic waves, which must dissipate in the Moon’s interior. Scientists have attempted to calculate the effects of Earth’s tidal forces on the Moon, but until recently none of the calculations had proven satisfactory. In a new study published in Nature Geoscience, researchers propose that the Moon has a zone of low viscosity located at its core–mantle boundary. That partially melted zone helps dissipate the heat created by the seismic-wave action. Although the model goes a long way toward matching simulations with observations, more refinements are needed, the scientists say. Their research could prove important to furthering our understanding of how planetary bodies formed.